Butyric acid

Butyric acid, (from Greek βουτυρος = butter) IUPAC name n-Butanoic acid, or normal butyric acid, is a ppm.

Butyric acid is a hydrolysis leading to the unpleasant odor. It is an important member of the fatty acid sub-group called short chain fatty acids.

Normal butyric acid or fermentation butyric acid is also found as a hexyl parsnip (Pastinaca sativa); it has also been noticed in the fluids of the flesh and in perspiration.

It is ordinarily prepared by the fermentation of sugar or calcium carbonate added to neutralize the acids formed in the process. The butyric fermentation of starch is aided by the direct addition of Bacillus subtilis.

Butyric acid is used in the preparation of various Fisher esterification reaction.

The acid is an oily colorless liquid that solidifies at -8 carbon dioxide. The calcium salt, Ca(C₄H₇O₂)₂·H₂O, is less soluble in hot water than in cold.

There is an O₂ but a different structure. It has similar chemical properties but different physical properties.

Butyrate fermentation

Butyrate is produced as end-product of a fermentation process solely performed by obligate Louis Pasteur in 1861. Examples of butyrate-producing species :

• Clostridium acetobutylicum
• Clostridium butyricum
• Clostridium kluyveri
• Clostridium pasteurianum
• Fusobacterium nucleatum
• Butyrivibrio fibrisolvens
• Eubacterium limosum

The pathway starts with the hydrogen (H₂) are formed in the process and exit the cell. Then:

ATP is produced, as can be seen, in the last step of the fermentation. Three molecules of ATP are produced for each glucose molecule, a relatively high yield. The balanced equation for this fermentation is:

C₆H₁₂O₆ → C₄H₈O₂ + 2CO₂ + 2H₂

Acetone and butanol fermentation

Several species form butanol in an alternative pathway, which starts as butyrate fermentation. Some of these species are:

• Clostridium acetobutylicum: the most prominent acetone and butanol producer, used also in industry
• Clostridium beijerinckii
• Clostridium tetanomorphum
• Clostridium aurantibutyricum

These bacteria begin with butyrate fermentation as described above, but, when the pH drops below 5, they switch into butanol and acetone production in order to prevent further lowering of the pH. Two molecules of butanol are formed for each molecule of acetone.

The change in the pathway occurs after acetoacetyl CoA formation. This intermediate then takes two possible pathways:

• Acetoacetyl CoA → acetoacetate → acetone, or
• Acetoacetyl CoA → butyryl CoA → butyraldehyde → butanol.

Butyric acid function/activity

Highly-fermentable fibers like oat bran, pectin, and guar are transformed by colonic bacteria into short-chain fatty acids including butyrate.

Butyrate has diverse and, it seems, paradoxical effects on cellular proliferation, Atkins diet are known to reduce the amount of butyrate produced in the colon.

Butyric acid has been associated with the ability to inhibit the function of histone deacetylase enzymes, thereby favouring an acetylated state of histones in the cell. Acetylated histones have a lower affinity for DNA than non-acetylated histones, due to the neutralisation of electrostatic charge interections. In general, t is thought that transcription factors will be unable to access regions where histones are tightly associated with DNA (ie non-acetylated, e.g., heterochromatin). Therefore, it is thought that butyric acid enhances the transcriptional activity at promoters, which are typically silenced/downregulated due to histone deacetylase activity.

This article incorporates information from the 1911 encyclopedia.

References

See also

• Indole-3-butyric acid